Social media are media for social interaction and typically employ web-based technologies to turn communications into dialogs between users. Content in social media systems is generated by users, of which there may be hundreds of millions in any given social media system. This content posted by users can provide valuable information as part of the World Wide Web in real-time. However, as there are no controls on joining social media systems, there are many users—indeed the majority—that are not authorities on any given topic. Furthermore, many user accounts may not even belong to a real person. Spam and aggregator accounts of varying degrees of severity and deception exist in large quantities, adding little or no value to the information provided by a social media service. In stark contrast to all of this noise in the social media signal, many end user scenarios hinge on finding users that are the most authoritative on a given topic. Social authority is developed, for example, when an individual or organization establishes themselves as an expert in a given field.
Most social media systems (Twitter®, for example) are organized using social graphs and often report some properties of users such as the number of followers and the number of times a user's content has been passed along in the system. One form of ranking user content is to use these social graph metrics. However social graphs are prone to simple spamming, and even in the absence of such spamming tend to be dominated by celebrities.